Federal inspectors found no violations as they delved into the reactor shutdowns in January at Calvert Cliffs in Southern Maryland, the Nuclear Regulatory Commission said Friday.
An electrical malfunction caused both of the nuclear power plant's reactors to shut down during a snow and ice storm in January, sending natural gas prices soaring as energy providers rushed to make up for the lost electricity production. The commission sent a three-person special inspection team to the plant the following week.
The inspectors concluded in their letter to Calvert Cliffs that "overall, equipment functioned as designed, personnel acted to [maintain] plant safety and security in response to the severe weather event," and the plant "took appropriate actions to review and address the causes of the dual-unit trip."
The agency's on-site inspectors will follow up on related issues, including the reason one reactor's digital turbine control system failed during the shutdown.
Kory Raftery, a spokesman for plant owner Constellation Energy Nuclear Group, said by email Friday that "we are committed to implementing any procedural or performance improvements that might make our facility even safer moving forward."
The nearly 40-year-old Calvert Cliffs plant has suffered several unplanned outages since the summer of 2012, largely involving control-rod problems.
Tim Judson, executive director at the Nuclear Information and Resource Service, a watchdog group in Takoma Park, said regulators seemed to have given Constellation "a pass" in the latest case because the plant had never before had the specific kind of electrical failure it experienced in January. He's not sure he agrees that the event doesn't raise larger safety concerns.
"But if we can take NRC at their word, it sounds like Calvert Cliffs really isn't the 'reliable, full-time' power source Constellation likes to say it is," he said. "This outage came during a really cold winter right before the polar vortex, and the shutdown caused a large spike in natural gas and electricity prices, which really hurt consumers."